//Symbol.toStringTag 区分类型
console.log(Object.prototype.toString.call('foo')) //[object String]
console.log(Object.prototype.toString.call([]))
console.log(Object.prototype.toString.call(1))
console.log(Object.prototype.toString.call(true))
console.log(Object.prototype.toString.call(null))
console.log(Object.prototype.toString.call(undefined))

let myExports = {}
//为了更进一步区分不同的Object对象类型
Object.defineProperty(myExports,Symbol.toStringTag,{value:'module'})
console.log(Object.prototype.toString.call(myExports));